A toxic algae bloom at an Indiantown marina earlier this month had toxin levels 100 times higher than the level safe for human contact according to the Florida Department of Health.

Predictably, some coastal media and “environmental” spokespersons were quick to blame releases from Lake Okeechobee.

They also somehow missed the fact that the Indiantown marina algae bloom had already been treated with an algaecide, and the day after the news broke, toxin levels had fallen back below the concentration the Environmental Protection Agency considers safe for swimming.

On Aug. 3, the Florida Department of Environmental Protection sampled an algal bloom on the C-44 canal at Timer Powers Park Boat Ramp. The dominant taxon was Microcystis aeruginosa. Microcystin toxin levels were 800 parts per billion (ppb). The bloom was treated with algaecide.
On Aug. 8, Florida Department of Health in Martin County issued a health alert, warning the public to stay away from the algae bloom.
On Aug. 9, the water was sampled again where the bloom had been treated, and toxin levels had dropped to 5.6 ppb.

The Environmental Protection Agency (EPA) considers microcystin toxin levels above 1.0 ppb to be unsafe for drinking water and levels above 8.0 ppb to be unsafe for recreational contact (swimming).

The Aug. 8, TC Palm story claimed headlined “Army Corps’ Lake Okeechobee releases carry toxic algae to Timer Powers Park in Indiantown” stated “toxic algae from Lake Okeechobee is polluting the C-44 canal at the Timer Powers boat ramp in Indiantown.” The story claimed to be referencing the state health alert. However, while the Florida Department of Health alert did warn the public about the algal bloom, it did not blame the algae bloom on lake releases.

In an Aug. 9 interview with WPTV, Mark Perry of the Florida Oceanographic Society claimed Army Corps of Engineers had opened the Port Mayaca floodgates to discharge nearly 9 million gallons of water from Lake Okeechobee into the C-44 canal “in an effort to lower the lake.”

According to the U.S. Army Corps of Engineers, since April the only releases from the lake to the C-44 canal have been to maintain the level of the canal for navigation, for water supply when local rainfall was not sufficient and to keep the C-44 reservoir STA hydrated when local basin runoff was not sufficient.

Consider: One inch on Lake Okeechobee equals about 12 billion gallons of water. On the scale of the Big O, 9 million gallons appears negligible. It would seem foolish for USACE to release a paltry 9 million gallons and expect any change in the lake level.

In that same news story, Scott Watson at the Indiantown Marina explained algae blooms are common at the marina. “I’ve owned and operated Indiantown Marina for 21 years,” Watson told WPTV. “It comes and goes. It’s nothing to get excited about, as far as I’m concerned.”

In fact, by the time the interview aired, toxins at the marina were already back to safe levels for “human recreational contact.” (According to information shared at meetings of the Florida Blue-Green Algae Task Force, EPA defines “human recreational contact” as the level safe for small children to swim in.)

Blaming the lake for coastal water problems is nothing new. Many coastal residents – and politicians -- would rather use Lake O as a scapegoat than consider that their own lawn fertilizer and septic tanks could be sending excess nitrogen and phosphorus into waterways and fueling algal blooms.

As long as coastal media (and politicians) blame the problem on Lake O releases, there’s little public pressure to find and address the source of phosphorus and nitrogen FEEDING the algae blooms.

Until we find a way to restrict the food sources, the algae bloom problems will continue. According to the top scientists on the Florida Blue-Green Algae Task Force, cyanobacteria (commonly called blue-green algae) are everywhere. They are part of the natural ecosystem. They are in all lakes, streams, canals and rivers – in all water that is not sterile.

Cyanobacteria move from one body of water carried by boats and wildlife. Some cyanobateria are present in lake releases, just as cyanobacteria are carried into the lake with flows from the Kissimmee River, Fisheating Creek, Taylor Creek and even backflow from the C-44 canal. (When the lake is below 14 feet, water backflows from the C-44 into the lake at Port Mayaca.) Even a “pristine” waterway is not free of cyanobacteria. These microscopic organisms are the base of the food chain and the oldest life form on the planet.

The U.S. Geological Survey (USGS) has documented 28 species of cyanobacteria in the Lake Okeechobee Waterway which includes the Caloosahatchee River, Lake Okeechobee, the C-44 canal and the St. Lucie River. About 25% of species of cyanobacteria are capable of producing toxins, according to USGS. Even those capable of producing toxins may not always do so.

Linking the Indiantown algal bloom to Lake O releases is a stretch. Indiantown is about 12 miles from Lake Okeechobee. While there was an algal bloom near the Port Mayaca Lock earlier in the month, the toxin levels were considerably lower.

A sample taken Aug. 1 in the C-44 canal on the canal side near the Port Mayaca lock tested 12 ppb microcystin. A sample taken inside the structure that day had 16 ppb. The bloom was treated with algaecide.

A sample taken near the Port Mayaca Lock on the canal side on Aug. 4 had toxin levels of 1.6 ppb. A sample taken inside the structure the same day had no detectable toxins.

Algal blooms in or near water control structures are common. Algal blooms are more likely where there is little water movement. That includes water control structures, dead end canals and marinas.

For a bloom to intensify, the algae need food – phosphorus and nitrogen. There’s plenty of phosphorus in the water from Lake Okeechobee, and SFWMD data show historically the water in the C-44 canal has been as high or even higher in phosphorus than the Lake O water. So the C-44 doesn’t need lake water to provide the phosphorus.

Microcystis aeruginosa, the cyanobacteria dominant at the Indiantown Marina is not capable of “fixing” nitrogen from the air. (Some species of cyanobacteria can do this.) A Microcystis bloom means there is a ready supply of both phosphorus and nitrogen in the water. A Florida Atlantic University study found a connection between higher nitrogen levels in the water and increased toxins in algae blooms.

Since the bloom at the marina had higher toxin levels than the bloom at Port Mayaca, it would stand to reason the nitrogen levels at the marina were higher. Shouldn’t someone be trying to determine where that nitrogen came from?